1. Technical Field
The present invention relates to an electro-optical device such as a liquid crystal device or the like. In addition, the invention further relates to an electronic apparatus that is provided with an electro-optical device. An example of a variety of electronic apparatuses to which the invention can be applied includes but not limited to a liquid crystal projector.
2. Related Art
As a typical example thereof, an electro-optical device of the related art has the following configuration. A plurality of pixel units (i.e., pixels) is formed in a pixel region (i.e., pixel area) over an array/element substrate. A peripheral region (i.e., peripheral area) surrounds the pixel region. A variety of peripheral circuits such as a driving circuit and a test circuit, though not limited thereto, are provided in the peripheral region. The driving circuit provides a driving force to the plurality of pixels for the operation thereof. The test circuit is used for testing the electro-optical device. A plurality of external connection terminals such as external circuit connection terminals and test terminals is provided at the peripheral region. The plurality of external connection terminals is used for the purpose of supplying various kinds of signals from the outside to the peripheral circuits. For example, an external device/circuit that is electrically connected to some of the external connection terminals supplies an input signal to the peripheral circuit. The plurality of external connection terminals is also used for the purpose of outputting a signal from the peripheral circuit to the outside (e.g., external device). An example of an electro-optical device of the related art that has the configuration described above is described in JP-A-2007-79541.
An electro-optical device of the related art that has the external connection terminals described above is susceptible to electrostatic damage. For example, if electrostatic charges are generated near an electro-optical device of the related art and then applied to any external connection terminal thereof to reach a peripheral circuit thereof without any intention to do so, which might occur accidentally during the assembly of the electro-optical device, during the testing thereof, or during the shipment thereof or other transportation thereof, the circuit characteristics (e.g., operation performance, though not limited thereto) of the peripheral circuit may be degraded, or even worse, the peripheral circuit may be electro-statically damaged. As a known technical solution to such an electrostatic problem, a resistance/resistive element is typically provided on an electric wire/line that is connected to the external connection terminal at its one end and the peripheral circuit at its other end. The resistance element that is provided on the electric wire between the external connection terminal and the peripheral circuit protects the peripheral circuit against electro-static damage. An example of such a configuration is described in the above-identified JP-A-2007-79541.
However, the resistance element described above has the following disadvantage. The resistance element is formed as, for example, a part of the electric wire extending between the external connection terminal and the peripheral circuit. The part of the electric wire that is formed as the resistance element between the external connection terminal and the peripheral circuit is made of a relatively high resistance material such as conductive polysilicon, though not limited thereto. The part of the electric line that is formed as the resistance element between the external connection terminal and the peripheral circuit has a pattern that is formed in the peripheral region. Accordingly, the size of a layout area at which the resistance element is formed in the entire area over the substrate is relatively large, which makes it practically impossible or at best difficult to make the size of an electro-optical device of the related art smaller. That is, because of a comparatively large pattern size of the part of the electric wire that is formed as the resistance element between the external connection terminal and the peripheral circuit, an electro-optical device of the related art has a technical difficulty in reducing the size thereof.